Watch ULA abort a rocket launch at the last moment

The team had even declared 'liftoff.'

United Launch Alliance, YouTube

Most rocket launch aborts are largely uneventful, but United Launch Alliance’s latest was... dramatic. The spaceflight outfit had to abort its NROL-44 mission (via Parabolic Arc) just three seconds before it was due to start, with the Delta IV rocket’s initiators already covering the vehicle in flames — the crew even declared “liftoff” without realizing that the mission had been cut short. The engines never ignited, ULA said.

It’s not initially clear what the problem was, but it will take at least a full week to try launching again. This shouldn’t affectt SpaceX’s plan to launch an Earth observation satellite on August 30th (today, if you’re reading in time) at 7:18PM Eastern from a nearby launchpad at Cape Canaveral. SpaceX also hoped to launch a Starlink mission earlier in the day, but that was pushed back due to bad weather.

ULA’s rocket was carrying a secret National Reconnaissance Office payload that’s believed to be a signal intelligence satellite.

Aborts like this are very rare. At the same time, they illustrate just why spacecraft designers conduct so many tests, and why there are loads of preflight checks. Spaceflight is still relatively young and prone to failure, and a well-established track record is far from a guarantee that everything will run smoothly.